Crane



July 8, 1952 ORLOFF 2,602,552

CRANE Filed Sept. 20, 1950 2 SHEETS -SHEET 1 INVENTOR.

A. ORLOFF July 8, 1952 CRANE 2 SHEETS-SHEET 2 Filed Sept. 20, 1950 anINVENTOR. 163M, 0% BY M ofimck Fucq. 4-

Patented July 8, 1952 fururao STATES CRACNE f Arthur Orloff, Nunda, N.Y. Application September 20, 1950, Serial No. 185,728v

The invention relates to cranes and more particularly to cranes of thefull rotating type in which the crane structure is mounted on a baserotatable on or about a mobile base or chassis.

Full rotating cranes are usually mounted on truck chassis, endless treadpropelling structures, wheeled frames, or other forms of traveling ormobile bases that are narrower than their lengths because of thelimitations in width of ordinary highway equipment. Steering mechanisms,and other factors also usually necessitate the wheel base be ofsubstantially greater length than wheel tread.

In cranes of the character above described, the stability f the crane,or its capacity to hold a certain load varies considerably as the craneturns or swings in its complete revolution. Invariably the stability ofthe crane is much greater when the boom or load is over the ends, or ina plane of the long or longitudinal axis of thesupporting base. When theboom swings over the'transverse axis of the base or laterally thereof,the stability is reduced. This can be easily appreciated when weconsider that the load swings around a circular path, but the base ofthe support of the load is non-circular and of rectangular formconsiderably narrower than its length. To improve the side-stability, acommon practice of crane manufacturers is to provide retractableside-arms or Outriggers, either manually adjustable or movable by powerto provide increased bearing area for the support to permit the crane toswing its maximum load in a complete or full circle. The use ofoutriggers is objectionable because when they are in operation, thecrane is temporarily im mobilized for traveling.

It is common practice among crane manufacturers to rate their cranes onthe basis of the minimum or cross-cross-stability of the apparatus. Thispermits the rated load to be safely swung in a complete circle withoutdanger of tipping over and is known as free-stability. To increase thefree-stability" it is the usual practice to add counterweight to therear end of the crane carrying swinging base. This practice, however,adds considerably to the total weight of the crane and still does notreduce or remove the great differential existing between the sidestability and end-stability of the crane.

The object of the present invention is to provide a crane of the fullrotating type whose cross or transverse stability is substantially thesame as its lengthwisestability so that the crane will swing in a fullcircle any load that it can pick up over its ends with the result thatits end sta- 4 Claims. (01.212 59) bility can be used as a basis forrating the capacity of the crane, so that weight for weight, the

crane embodying my invention has much greater rate capacity and willsafely swing any rated load in any of its'angular positions relative toits mobile supporting base. More particularly, according to the presentinvention, the ability of the crane to handle a load across itstransverse axis of the same magnitude as can be handled along itslongitudinal axis is accomplished by providing means for shifting therotating or crane carrying base of the machine relative to thetransverse axis of the traveling base of the machine in such a directionthat the center of gravity of the rotating base is so disposed relativeto the traveling base that the loaded crane will have substantially thesame transverse stability as longitudinal stability. Q 7 1 The inventionfurther consists in the several features hereinafter set forth and moreparticularly defined'by claims'at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation view of a crane embodying the'inventionshowing the load applied in the longitudinal axis of the traveling base,parts being broken away;

Fig. 2 is a detailed horizontal sectional view taken on the line 2--2of. Fig. 1;

Fig. 3 is a side elevation view similar to Fig. 1 showing the loadapplied along'the transverse axis of the traveling base, parts beingbroken away;

Fig. 4 is a detailed vertical sectional view taken on the line 4-4 ofFig. 2;

Fig. 5 is a comparative diagrammatic view of the load paths of theimproved'crane and the usual crane.

Referring to the drawings, the numeral 6 designates generally anysuitable form of traveling or mobile base, 7 the rotating base carryingthe load supporting boom 8.

The traveling base 6 is here shown as a truck chassis having a frame 9supported by the running gear including front wheels I0 and rearpropelling wheels I I driven through any suitable transmission by theengine located in the cab l2,

the length of the wheel base being greater than its width. The rotatingbase I is provided with the usual power operated hoist drum (not shown)controlled by the operator in the cab iii of said base and over which ahoist cable i4 is wound, said cable extending upwardly over a guidesheave 15 at the point of the boom 8 and downwardly therefrom to theload L.

According to the present invention, the axis of rotation of the rotatingbase is adapted to be" shifted laterally of the travelling base, so thatthe center of gravity or weight of said rotating base is also shiftedrelative to said traveling base during the swinging or rotation of therotating base. For accomplishing this purpose, the base member I6 of therotating base 1 is mounted to turn on a subbase I! which is shiftablymounted on the traveling base 6. As'shown in Fig. 4, the base member itrotates on rollers 18 interposed between the base members i6 and I7 andhas a center pin or shaft 19 keyed thereto, which shaft is journalled inthe base member I! and projects below the same. The rotating basei maybe swung or rotated relative to the traveling base 6 by any suitableswing mechanism as, for example, a ring gear 20 fixed to the sub-base l1and meshing with a pinion 2! on a shaft 22 journalled in the base memberl6 and carrying a drive gear 23 driven in any suitable manner from theprime mover in the cab I3. The subbase H has laterally disposed sidebase flanges 24 slidably .mounted in transversely disposed spaced guidegrooves 25 in guides 213 suitably mounted on and secured to thetraveling base 5,.

The lower end of the shaft l9 has a crank arm 21 keyed thereto andcarrying a pinv 28 pivotally connecting its outer end with one end of alink 29 whose other end is pivotally connected by a pin 33 to an anchorbracket 3i secured to the frame 9 of the traveling base 8. Thedisposition of the crank 21 relative to the traveling base 8 when therotating base is in a position in which the boom 8 ,is disposedsubstantially in line. with the longitudinal axis A of the travelingbase is shown in Fig. 1 in which R. designates the load radius and S thestability arm between the balancing point B and the loadL. The center ofgravity or Weight ofthe rotating base is indicated bythe arrow G.. Now,if. the swing gear mechanism is operated to turn the rotatiing base "iin a counterclockwise direction, as viewed in Fig. 2, the shaft l9turning with the base 7 acts to turnfthe crank 21in] the same direction,but since said crank is attached to: the free end of the link 29, theshaft l9, under the restraintof said link, togetherwith the base member[6 will move laterally on. the sub-base ll toward the anchored end off/the link 29;, sothatwhen the base ,6 has made a quarter turn and theboom 8 is alined-with the transverse axis T of the traveling base, theposition of the rotating base and its load relative to thetraveling baseis shown in Fig. 3. In this position it will be noted that the stabilityarm SB between the balancing point BB of the base 6- and theload L isthe same as the stability arm S and that the center of gravity G hasbeen displaced further away from the longitudinal center line of thebase 6 than it would be were the base I mounted to rotate on an axisalined with the longitudinalcenter line of the truck, thus securingincreased stability.

, It will also be noted that in the position shown in Fig. 3 the loadLhas been moved closer to the base 6 because of the transversemovementof the base I. In the ordinary crane the load moves in a full linecircleC, as shown in- Fig-5, while in the improved crane the load moves inthedotted line elliptical path E. Thesame stability effect and the lateralmovement of the base 1 and its ioad're lative to the base} issecuredwhen the base i; is turned in; a, clockwise direction. Thus rotation'of,base- 6 in either sense of direction will causethe, pin orcenter shaftii! to move along the transverseaxis: Tjwith an 4 increasing tendency ormoment of stability of the entire weight of the rotating base I withrespect to the balancing point BB. Concurrently with this, the load L,although rotating radially about shaft l9, by virtue of sub-base l1sliding along the travelling base 6, will have reduced the stability armSB. The stability arm SB is reduced to substantially the amount wherethe moment of the load L about balancing pointB will be balanced by theweights of the rotating base I and the travelling base 6 about this samepoint. Practically, the length of the lever or crank 21 is such that astate of equilibrium will exist about balancing points B and BB. It canbe readily seen that inasmuch as the entire mass of the rotating base ismoved rearwardly to aid the cross stability in the transverse axis T inconjunction with the inward movement of the load L, relative to the base6, the effect of the lateral shift mechanism is two-fold. First, itmoves the rotating base backwards. Secondly, it brings the load closerto the base 6. Consequently, as shown by the dotted lines in Fig. 5, theload will move in a substantially elliptical path.

In practice it is not necessary that load radius beexactly the samecrosswise as lengthwise. However, it is a distinct advantage fora fullcircle crane to swing its capacity load in a full swing which isaccomplished herein with an increase in the rated capacity of the crane.Y

I desire ittotbe understood that this invention is not to be limited toany particular form or arrangement of parts except in so far as, suchlimitations are included in the claims.

What Iclaim as my invention is;

1. In a full rotating crane, the combination of a, traveling base, a.rotating base having a load carrying boom, means for mounting saidrotating base on said traveling base for rotating and shifting movementsrelative thereto, and means operated byth'e rotation of said rotatingbase for shifting said rotating, base relative to said traveling baseduring the swinging movement of the load from a position alongthelongitudinal'axis. of, the traveling base. to one across said. wherebysaid rotating base and load are shifted rearwardly along a transverseaxis of said traveling base to increase thestability of the crane whenthe load carrying boom is disposed transversely of said traveling base.

2. In-a full rotating crane, the combination of a traveling base, arotating basehaving a load carrying boom, a sub-base mountedto shifttransversely of said traveling base androtatably supporting saidrotatingbase, means for rotating said rotating baserelative to said sub-base,and means operated by the rotationof the rotating base for laterallyshifting said: sub-base relative to said traveling base to; compensatefor decreased stability of thecrane as theload carryingboom swings froma positionalong the longitudinal' axis of the traveling base toaposition across said: axis.

3; In a fullrotatingrcrane; the combination of a traveling base,arotating base having: a load carrying boom, a sub-base laterally.slidably mounted 'onsaid traveling baseaand: carrying said rotatingbase, means forturning said rotating base relative to said sub-baseandsaid'traveling base, 'apivot shaft for the. rotating" base journalledin: said; sub-base, andimeans. operativelyconnecting said pivot shaft;with the travcling: base wherebyrotation: of saidirotatingrba shiftssaid sub-base laterally relative to said traveling base and in adirection to effect increased stability of the load carrying boom as itmoves to a position transversely of the longitudinal axis of saidtraveling base.

4. In a full rotating crane, the combination of a traveling base, arotating base having a load carrying boom, a sub-base slidably mountedon said traveling base for lateral movement relative thereto andcarrying said rotating base, a pivot shaft for said rotating basejournalled in said sub-base, a crank mounted on said shaft and a linkoperatively connecting the free end of said crank with a part of saidtraveling base,

and means for rotating said rotating base rela- 15 tive to said sub-baseand said traveling base and as a consequence operating said crank andlink to shift said sub-base laterally of said traveling base as the boomon said rotating base is swung from a position along the longitudinalaxis of the traveling base to one across said axis, said shiftingmovement acting to move the load of the boom closer to said travelingbase in the transverse position of said boom to thereby provideincreased lateral stability for the crane.

ARTHUR ORLOFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date I 1,520,194 Matthews Dec. 23,1924 2,295,769 Zeilman Sept. 15, 1942 2,472,726 Russell June 7, 1949

